Young Harry Potter fans who are disappointed that JK Rowling's new book, The Casual Vacancy, due out tomorrow, is aimed at adults with not a spell in sight, will be heartened by the news that she will be returning to children's fiction with her next book.

Speaking on Radio 4's Today programme this morning, the author said that "I think it very likely the next thing I publish will be for children." She added, "I have a children's book that I really like. It's for slightly younger children than the Potter books."

However, she was less definite about whether she would be returning to the world of Harry and Hogwarts at any point, saying that she is "very averse to the prequel/sequel idea", while not ruling out what she called a "side-step".

"Where Harry's story is concerned I am done, now if I had a fabulous idea I would do it. I don't want to go mechanically back into that world and pick up loads of odds and ends, then glue them together and say 'Here we go, we can sell this'. It would make a mockery of what those books mean to me."

Rowling also said that it was possible she might do a "director's cut" on a "couple of the Potters" that needed more time spent on them. "I definitely knew that they needed another year," she said. "I had to write on the run and there were times when it was really tough."

While Rowling's new book is most definitely aimed at adults – it's slice-of-life social realism set in a West Country village with a liberal scattering of swearwords - Harry Potter fans did get a filip this week with the arrival of new content on her online magical world, Pottermore. Read our Pottermore correspondent's verdict on the latest additions to the site.